Multiple radio control



Oct. 27, 1931.

A. J. MACY MULTIPLE RADIO CONTROL Filed March 14, 1929 5 m u L/ Z morePatented Oct. 27, 1931 UNITED STATES.

PATENT OFFICE ALFRED J. MACY, or EVANSTON, ILLINoIs, ASSIGNOR, BY manorAND MESNE AS- sIeNMENrs, or NINETEEN SIXTIETHS T0 JOSEPH L. LYNCH, orOAK PARK, IL- LINoIs, AND FORTY-ONE SIXTIETHS 'ro BARITONE RADIOcoRroRArIcN, or CHICAGO, ILLINOIS, A CORPORATION or ILLINOIS M'U'LTIPLERADIO CONTROL Application filed March 14, 1929. Serial No. 346,838.

This invention relates to improvements 1n multiple radio controls, andcontemplates articularly the provlsion of an mproved method of and meansfor providmg selective radio entertainment from various broadcastingstations, in a plurality of places, isolated from each other, if sodesired, from a unitary source of rece tion. The present invention ishighly desira l e for use In hotels, apartment hotels, and the like. 0

An object of this inventlon is to prov de means whereby individual radioentertainment is made available in the various rooms or apartments of abuilding and each user thereof may choose his program from any one of anumber of radio recelvmg sets located at a centraland tuned to differentradio broadcasting stations. a

It is a further object of this lnventlon to provide means whereby eachuser may control the volume of the output of his loud speaker withoutappreciably changmg the constants of the circuit connectmgthe loudspeaker with the receiving set while doing so.

It is also an object of the invention to provide a method of mounting aloud speaker in a room so that a wall or the ceiling of the room coactswith the loud speaker in voice and music reproduction.

It is also an object of this invention to provide a method of mounting aplurality of loud speakers in a room so that an artistic efl'ect isproduced, and so that music. 1S reproduced -without efli'ects analogousto those of glare and shadows in illumination.

The invention includes these andother features of construction andcombinations of parts hereinafter described and shown in a preferredform in the drawmgs and as more particularly indicated in the clalms.

In the drawings Figure 1 illustrates somewhat diagrammatically anembodiment of my invention.

Figures 2 and 3 show, in elevation and In section, respectively, themanner of supporting a loud speaker andits switch control means on awall of a building.

As shown in the drawings, the numeral 1 indicates a plurality ofradio-receiving sets,

as many as may be desired, located at some common point, and each settuned to a ditlerw ent radio broadcasting station. To each set there isconnected a pair of trunk or main lines 2 which are carried to theseveral floors of a hotel, or the like, and from the trunk lines go outbranch lines 3 to the'rooms on each floor, so that the occupant of aroom may connect a loud speaker 10 through a selector switch 4 and aselected pair of branch and trunk lines to receive the program output ofa selected receiving set. The selector switch 4, is typical, andconveniently shows the manner in which the branch lines 3, terminatingin contacts 5, may be connected through the switch blades 6 to theterminal equipment in the room.

A potentiometer 7, comprising a resistor 8 and an adjustable contactswitch 9, has its resistor 8 connected to the switch blades 6, so thatthe resistor 8 becomes the terminal impedance or load of the pair oflines to which the switch is connected. The loud speaker or reproducer10 is connected to the resistor 8 through conductors 11 and theadjustable contact switch 9, and it will be evident to those familiarwith the art that the volume of the reproduced music may be con trolledby varying the position of the switch 9 to vary the potential at theterminals of the conductors 11.

It is important to note that the resistor 8 is a substantially constantnon-inductive terminal impedance or load for the pair of linesconnecting it to the output sides of the radioreceiving set. Thereslstor 8 shunts the distributed capacity of its connected pair oftrunk and branch lines, and in doing so it improves the quality of thereecived signals. The resistor 8 becomes the immediate source of thedriving voltage of the reproducer 10, and the complex variations in theimpedance of the reproducer 10 have practically no effeet on theregulation of the transmission system, and therefore do not producedistor tion and poor quality in the transmitted signals. This is a veryimportant and beneficial result in a program distributing system forhotels and apartments because when the combination just'described isemployed, the several trunk and branch lines may be installed by theelectricians installing the power and light wiring, and the cost of theinstallation is not made prohibitive by calling for unusual skill andcare.

The potentiometer 7 also provides means for substantially matching thenormal impedance of the reproducer with that of the output circuit ofthe receiver. It is also important to note that variations in the energytaken by the reproducer 10 following manipulation of the switch 9 do notappreciably eflect the regulation of the connected system and do not,therefore, annoy other users connected to the same receiver.

The potentiometer 7 with its resistor 8 and its adjustable contactswitch 9 may be mounted with the selector switch 4 on a small panel 12;and the assembled units may be secured to wall 13 of a room, as shown inFigures 2 and 3, or they may be incorporated in the base of a portablereproducer 10, for the convenience of invalids.

In Figures 2 and 3 of the drawings, a reproducer 10 of the disk or drumtype is shown housed in a recess 14 in a wall 13 of a room, so that thewall transmits the vibrations of the reproducer and coacts with it inthe reproducing of music and the voice. It has been found that when arelatively small and inexpensive reproducer is so mounted thecombination reproduces music and voice of volume and quality equivalentto that of large and more expensive reproducers not so combined.

lVhen a plurality of reproducers 10 are housed in recesses in theceiling 15 of a room in the manner of Figure 3, and distributed in theceiling in the manner indicated diagrammatically in Figure 1, music isheard equally well in all parts of the room, and there are no annoyingdiilerenees in sound intensity within the area treated. The ceilingtransmits the vibrations of the reproducers, and coacts with them in thereproducing of music and voice. It will be understood that thedistribution indicated diagrammatically is merely suggestive, and thatthe reproducers may be distributed as desired to best meet a particularsituation without departing from the spirit of my invention. Thereproducers 10 are connected in parallel, and may be controlled by asingle potentiometer 7 or the output of each may e controlled by apotentiometer 7 in its own circuit, so that differences in reproducerimpedances and characteristics may be compensated by different settingsof the several adjustable contact switches 9, and the output of eachadjusted to produce a desired blending of their outputs. When aplurality of reproducers are housed in the ceiling in the mannerdisclosed, the room may be amply filled with music although the outputfrom each speaker is but moderate and directional effects will bepractically absent. And since the horizontal component of the output ofeach reproducer is relatively small, the total output may be largewithout disturbing persons in adjacent rooms and hall ways.

When my program broadcasting system is installed in an apartment hotel,it may be desirable that the system, as a whole, be governed from acentral point to reduce the outated at some predetermined time by meansof a clock 16 suitably connected to the switch lever 9 through anoperating link 17. The lever 9 may be shifted in one step, or in severalsteps, at certain time intervals, to warn the users of the system thatit is about to be adjusted for its final all-night condition, and toalso serve as means for indicating the time.

It will be obvious that the general principles herein disclosed may beembodied in other organizations different from those i1- lustratedwithout departing from the spirit of the invention as defined in thefollowing claims.

lVhat is claimed is 1. In combination, in a program distributing system,a radio receiving set, external output circuits for the set,reproducers, and

Illinois.

ALFRED J. MACY.

